1. Field of the Invention
This invention is generally directed to gladhands for operatively connecting the air brake lines of vehicles and especially trailers which are connected so as to be operated in tandem wherein the air brake system of the prime mover is connected through airlines associated with each trailer vehicle. The gladhands are selectively connected with one another so as to provide a leak-free connection in the brake system between the vehicles or trailers. The gladhand of the present invention is more specifically directed to a swivel type gladhand which is positively torsioned or urged into a closed position when not coupled to another gladhand and wherein the air outlet opening of the gladhand is sealed against a stop member having a seal element associated therewith when the gladhand is not in use. After the body portion of the gladhand of the present invention is moved to its non-use position wherein the opening therein is seated with respect to the seal of the stop members, a separate locking arm assembly is pivotally movable so as to urge the body portion of the gladhand into a clamped engagement with the seal thereby insuring that no air pressure will be lost through the outlet opening in the gladhand under normal vehicle operating conditions and thereby also protecting the seals of the outlet opening of the gladhand from contamination from dirt and debris.
2. History of the Related Art
In recent years, the transportation industry has found supportive legislation for enabling the use of tandemly connected trailers which are pulled by a single prime mover or tractor. The use of tandemly operated trailers makes more efficient use of the prime movers or tractors as well as conserves fuel and therefore offers an advantage over single trailer operations both in fuel economy and in the quantity of cargo which may be moved at a given time.
In order to operate the air brake systems associated not only with the prime mover or tractor vehicles but also of the trailers associated with each combination of tractors and trailers, it is necessary to provide a source of compressed air and to control the operable brake elements. A mechanical connection between air lines of the vehicles and trailers has been referred to as a gladhand assembly. The gladhand, in effect, provides a connection between each vehicle which is operated in tandem and connects the air lines in such a manner that there is no loss of air pressure at the connection therebetween. As the air systems of each of the trailers requires both a front and rear connection so that the trailers may be united in any random order, when a trailer is the last in a series of tandemly operated vehicles, it is necessary that the last or end gladhand be closed to prevent a discharge or loss of air pressure from the unused gladhand. Heretobefore, there have generally been three types of gladhand assemblies which have been utilized to close off the air line through a gladhand when the gladhand is not in use. More traditional type of shut-offs incorporate a valve member which is mounted upstream of the gladhand within the air brake system. In this type of an assembly, a separate valve member must be provided and maintenance along each vehicle air line system which not only increases the overall cost of the initial system but provides for increased maintenance costs and care which must be extended to insure the proper operation of the valves. Further, this type of an arrangement leaves the downstream gladhand exposed to atmosphere and also to road conditions when it is not coupled.
It is necessary to appreciate that gladhands are valve elements in and of themselves which elements must be in condition to be locked into sealed engagement with an associated gladhand when put to use. Therefore, the portions of the gladhands which form the locking components of a coupled gladhand assembly must be maintained free from dirt, debris, oil, grease and any other type of materials which would adversely effect the seated and sealing engagement of one gladhand with respect to another. Prior art systems that utilize an upstream type valve to close off the air line through a braking system and which do not provide some means for protecting the exposed surfaces of the unconnected gladhands have not proved to be adequate and often require increased maintenance to insure that dirt and debris is removed from the seal areas of the gladhands. In many instances, the seal components of such gladhands must be replaced after being contaminated by dirt and debris which is generated during the operation of a vehicle.
A second type of gladhand assembly incorporates a valve component as part of the gladhand itself. In these types of gladhands, a valve is provided through the body of a gladhand spaced from the interfacing surface of the gladhands. However, these types of valve assemblies, although providing for a reduced cost of initial installation, by including valve components as part of the gladhands to terminate airflow therethrough, do not solve the problem with maintaining or protecting the sealing or engaging surfaces of the gladhands when not in use which surfaces must be maintained to provide a safe and leak-free engagement between coupled gladhands.
A third type of system which is utilized to close off the air lines associated with non-used gladhands incorporate the use of "dummy" gladhands which are attached to vehicles adjacent to the conventional gladhands. In these types of systems, when the gladhands are not to be used, dummy gladhands attached by cable or chained to the vehicle are brought into place and coupled with the standard gladhands thereby sealing the interfacing surfaces between the conventional gladhands and the dummy gladhands. The dummy gladhands are different than the standard gladhands in that there are no air channels formed therethrough and therefore the connections simply terminate the air line at the point of the conventional gladhands. Unfortunately, the use of dummy type gladhands does not solve the problem associated with maintaining the interfacing surfaces of the conventional gladhands free of dirt and debris when not in use. The dummy gladhands are exposed to dirt and other elements when not used and therefore when the surfaces thereof are mated with conventional gladhands when in use, the dirt and debris built-up on the dummy gladhands contaminate the interfacing surfaces of the conventional gladhands. Further, such systems require that additional gladhand components be provided for each vehicle. This increases the overall cost and maintenancing of the entire air brake system.
Some examples of prior art patented gladhand assemblies are disclosed in U.S. Pat. Nos. 558,235 to Taylor et al.; 682,577 to Tripp; 3,960,365 to Horowitz; 4,109,673 to Horowitz et al. and 4,533,115 to Lissau.
The patent to Taylor et al. discloses a type of gladhand assembly having a valve seat formed integrally with the gladhand. In this structure, as discussed above, the member forming the valve seat will be continuously exposed to road debris, dust and dirt when the gladhand is not in use thereby possibly interfering with the proper operation of the valve assembly when the gladhand is used over a period of time. The patent to Tripp discloses a variation of an interior valve for use with a gladhand wherein the valve incorporates an elongated spring member which forces a body of the valve partially through the opening in the outlet of the gladhand. With this type of structure, the valve seat itself which surrounds the opening in the gladhand remains open to contamination by dirt, dust, road films and oils and therefore does not provide a leak-free type of connection which is necessary to insure the safe operation of the braking system.
The reference to Horowitz '365 discloses a type of gladhand assembly which also incorporates an interior valve which may be shut-off intermediate the base of a gladhand and the outlet opening therein. Although this type of gladhand assembly provides a safe shut-off for the air brake system when the gladhand is not in use, the interface portion of the gladhand remains exposed and may be contaminated as discussed above thereby requiring additional maintenance or resulting in the early failure of the seal elements associated therewith.
Horowitz et al. '673 discloses another type of combination gladhand and shut-off valve. The structure disclosed in this patent, however, was designed to overcome some of the disadvantages of the prior art and has incorporated a dust shield which is maneuverable into an overlapping relationship with the outlet in the gladhand. The system, however, requires the use of the separate valve member mounted within the gladhand assembly to effectively close off the air supply and prevent any leakage of the compressed air within the system. Such a gladhand assembly requires additional initial costs and maintenancing in that the separate valve member mounted within the assembly must be provided and maintained in order to insure an effective seal through the gladhand.
The prior art patent to Lissau discloses a further attempt to prevent the contamination of a gladhand interface valve by providing a plug member which is insertable through the opening in the gladhand to prevent the buildup of dirt in the area of the seal. In this reference, a reciprocating piston blocks the opening when the gladhand is in a non-use position. As with prior structures, however, this type of system requires that a valve member be provided within the gladhand assembly which valve member is slideably disposed relative to the opening in the seal. The operation of the valve member requires gaskets to be provided with respect to the valve body and the internal bore through the gladhand. These additional components not only add to the additional cost of the gladhand but also require separate maintenancing to insure the proper operation of the gladhand.
In an effort to overcome the problems and inefficiencies of conventional gladhands, the applicant of the present invention developed a swiveled and self-closing gladhand assembly. This gladhand assembly utilized a spring element to urge the body of the gladhand into a position, when not in use, wherein the outlet opening in the coupling member is urged into engagement with an exterior seal. Unfortunately, although this type of gladhand protects the sealing surfaces of the gladhand when not in use and also avoids the use of a separate valve member either combined with or remote from the gladhand, the closure is subject to air leakage at high operating pressures.